Fix video and audio playback problems on Firefox for Windows

This article applies to Windows Vista/7/8/8.1/10 users only.

Some versions of Windows are missing Windows Media Player and other media-related technologies needed to decode and play videos and music properly. Microsoft offers a Windows Media Feature Pack (for versions designated as Windows N and KN editions) and a Platform Update Supplement (for Windows Vista and Server 2008) that you can download to add this functionality.

Here are some problems that people have reported when the Windows Media Feature Pack is missing:

"Why is YouTube video blurry, low resolution, or black?"

"Why do I get Flash instead of HTML video?"

"Why doesn't Vimeo work?"

Solution

To resolve this, please download and install the Media Feature Pack or Platform Update Supplement that's appropriate for your version of Windows.

If you update Windows to a newer version, for example, from Windows 10 Version 1511 to Windows 10 Version 1607, you'll need to redownload and install the Media Feature Pack even though you installed it for the previous Windows version.